And yet no logs are logged. What am I missing here? There is reference on the internet to a variable called "logging_collector", but when I try and set that, postgres dies on startup with a FATAL: unknown variable.

Also, if you're building postgres from source, you might have better luck using a os x package from Fink or MacPorts. Doing all of the configuration yourself can be tricky for beginners, but the packages normally give you a good base to work from.